CVE-2026-27962

Published: Mar 16, 2026 Last Modified: Mar 17, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,1
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: none

Description

AI Translation Available

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a JWK Header Injection vulnerability in authlib's JWS implementation allows an unauthenticated attacker to forge arbitrary JWT tokens that pass signature verification. When key=None is passed to any JWS deserialization function, the library extracts and uses the cryptographic key embedded in the attacker-controlled JWT jwk header field. An attacker can sign a token with their own private key, embed the matching public key in the header, and have the server accept the forged token as cryptographically valid — bypassing authentication and authorization entirely. This issue has been patched in version 1.6.9.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0004
Percentile
0,1th
Updated

Single Data Point

Only one EPSS measurement is available for this CVE. Trend analysis requires multiple data points over time.

347

Improper Verification of Cryptographic Signature

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control Integrity Confidentiality
Potential Impacts:
Gain Privileges Or Assume Identity Modify Application Data Execute Unauthorized Code Or Commands
Applicable Platforms
All platforms may be affected
View CWE Details
Application

Authlib by Authlib

Product Information
Vendor Authlib
Product Authlib
Version Range Affected
To 1.6.9 (exclusive)
cpe:2.3:a:authlib:authlib:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
https://github.com/authlib/authlib/commit/a5d4b2d4c9e46bfa1…
https://github.com/authlib/authlib/commit/a5d4b2d4c9e46bfa11c82f85fdc2bcc0b50ae…
https://github.com/authlib/authlib/releases/tag/v1.6.9
https://github.com/authlib/authlib/releases/tag/v1.6.9
https://github.com/authlib/authlib/security/advisories/GHSA…
https://github.com/authlib/authlib/security/advisories/GHSA-wvwj-cvrp-7pv5